Opinion: Study finds cognitive bias in how medical examiners evaluate child deaths

A new study in the Journal of Forensic Sciences suggests the role medical examiners play in the criminal justice system is far more subjective than commonly thought. It also suggests their analysis might be tainted by racial bias.
Medical examiners (also known as forensic pathologists) make two determinations after conducting an autopsy: the cause of death and the manner. The cause of death, though sometimes ambiguous, is usually a fairly objective finding based on tests and observations well-grounded in medicine. But determining the manner of death can be much more subjective. In most jurisdictions, there are five possibilities for manner of death: undetermined, natural causes, suicide, accident or homicide. The evidentiary gap separating an accidental death from a homicide can be significant (the body was riddled with bullets) or razor-thin (whether the victim drowned or was drowned). Yet it’s enormously consequential, because a homicide designation usually means someone will be charged with a serious crime.

The new study was led by Itiel Dror, a cognitive neuroscience researcher at University College London who specializes in cognitive perception, judgment and decision-making. (His research team also included four forensic pathologists.) There are two parts to the study. In the first, the researchers looked at 10 years of Nevada death certificates for children younger than 6 and found that medical examiners were about twice as likely to rule a Black child’s death to be a homicide as a White child. The researchers then asked 133 board-certified medical examiners to read a vignette about a 3-year-old who was taken to an emergency room with a skull fracture, brain hemorrhaging and other injuries, and later died. All the participants received the same fact pattern, with one important exception: About half were told that the child was Black and had been left in the care of the mother’s boyfriend. The others were told the child was White and had been left in the care of a grandmother.

Of the 133 medical examiners who participated in the study, 78 said they could not determine a manner of death from the information available. Among the 55 who could, 23 concluded the child’s death was an accident, and 32 determined it was a homicide.

This is already a problem. Reliability is one of the key criteria the Supreme Court has said judges should consider in deciding whether to allow expert testimony. The same facts applied to different people should produce the same outcome. That clearly wasn’t the case in this study.